Colon-Targeted Delivery of Indole Acetic Acid Helps Regulate Gut Motility by Activating the AHR Signaling Pathway

Intestinal peristalsis is vital for gastrointestinal physiology and host homeostasis and is frequently dysregulated in intestinal disorders. Gut microbiota can regulate gut motility, especially through the tryptophan metabolism pathway. However, the role of indoles as microbial tryptophan metabolites in colonic function requires further exploration. Here, we show that the delivery of indole acetic acid (IAA) targeting the colon can improve gut motility by activating the aryl hydrocarbon receptor (AHR). To achieve colon-targeted delivery, Eudragit S-100 (ES) and chitosan (CS) were used as drug carriers. After optimisation, IAA-loaded ES-coated CS nanoparticles exhibited an encapsulation efficiency of 83% and a drug-loading capacity of 16%. These nanoparticles exhibited pH-dependent characteristics and remained stable in acidic conditions and the upper intestine. In simulated intestinal fluid (pH 7.4) and colonic lumen, considerable amounts of IAA were released after approximately 4 h. Compared with free IAA, the nanoparticles exerted enhanced therapeutic effects on gut movement disorders induced by loperamide. The efficacy of IAA treatment was attributable to the activation of the AHR signalling pathway and increased levels of AHR agonists. Furthermore, the oral administration of IAA-loaded nanoparticles promoted serotonin secretion and maintained the intestinal barrier function. The experimental outcomes demonstrate the efficiency of the proposed colon-specific delivery system and highlight the role of IAA, produced by gut microbiota metabolism, in regulating gut peristalsis through AHR activation.

Formulation Of Benzoyl Peroxide Microsponge-Based Transdermal Gel For Acne Infection And Its Evaluation

BACKGROUND

Benzoyl peroxide is a peroxide with antibacterial, irritating, keratolytic, comedolytic, and anti-inflammatory properties. When benzoyl peroxide is applied topically, it breaks down and releases oxygen, which kills the germs of Propionibacterium acnes. Benzoyl peroxide's irritating impact causes an increase in epithelial cell turnover, which causes the skin to peel and aids in the healing of comedones. Treatment for acne vulgaris involves the use of benzoyl peroxide.

OBJECTIVE

The research is aimed at studying the formulation of Microsponge gel preparation of benzoyl peroxide by using Carbopol 934 as a gelling agent and evaluation of microsponge gel formulation for its physicochemical properties.

METHODS

Microsponges of Anti-acne agent benzoyl peroxide drug were prepared by quasi-emulsion method, and in-vitro drug release using a suitable membrane model using a simple diffusion cell.

RESULT

Prior to drying, the microsponge was filtered and rinsed using distilled water. Formulation containing benzoyl peroxide and Eudragit RS100 with a ratio of 1:4 showed a high 87.5% drug content and 78.20 % yield. The drug content of the microsponge gel was found to be 84%. Microbiological study on S. aureus was conducted by the cylinder cup method and found good results. The in-vitro diffusion of microsponge formulations was sustained for 8 hours. The drug release rate for Eudragit RS-100 was reported to be 88.87% after 8 hours based on the polymer: drug ratio (4:1).

CONCLUSION

The quasi-emulsion solvent diffusion method was used to successfully prepare benzoyl peroxide microsponges using Eudragit RS100, Ethyl Cellulose, and HPMC K4M as polymers. The formulations with the highest medication concentration were made with the porous polymer Eudragit RS100.

Redox responsive poly(allylamine)/eudragit S-100 nanoparticles for dual drug delivery in colorectal cancer

Herein, we report redox responsive, colon cancer targeting poly(allylamine) (PA)/eudragit S-100 (EU) nanoparticles (PAEU NPs) (≈59 nm). These disulfide crosslinked PAEU NPs are developed via air oxidation of thiolated PA and thiolated EU, eliminating the need of any external crosslinking agent for dual drug delivery. PAEU NPs can effectively encapsulate both hydrophilic doxorubicin (DOX) and hydrophobic curcumin (Cur) drug with ≈85 % and ≈97 % encapsulation efficiency respectively. Here, the combination of drugs having different anticancer mechanism offers the possibility of developing nanosystem with enhanced anticancer efficacy. The developed PAEU NPs show good colloidal stability and low drug release under physiological conditions, while high DOX (≈98 %) and Cur (≈93 %) release is observed in reducing environment (10 mM GSH). Further, DOX and Cur loaded PAEU NPs exhibit higher cancer cell killing efficiency as compared to individual free drugs. In vivo biodistribution studies with Balb/C mice display the retention of PAEU NPs in the colon region up to 24 h presenting the developed approach as an efficient way for colorectal cancer therapy.

QbD-Enabled Systematic Development of Ileo-colonic Targeted Novel Mucoadhesive Microspheres of Flurbiprofen

BACKGROUND

Flurbiprofen (FLBP) is used in the treatment of ulcerative colitis and has a short biological half-life. Frequent intake of FLBP may lead to some serious gastric complications, which makes FLBP an ideal candidate for sustained release preparation to the Ileo-colonic region of the gastrointestinal tract (GIT).

OBJECTIVE

The objective of this study was to investigate the potential of Eudragit coated chitosan microspheres in delivering Flurbiprofen in a sustained manner to the Ileo-colonic region of the GIT for treatment of ulcerative colitis.

METHODS

In the present study, mucoadhesive chitosan microspheres were prepared using the emulsion solvent evaporation method by varying different process parameters. Optimized chitosan microspheres were coated with Eudragit L-100 and Eudragit S-100. A 32 full factorial design was applied for optimization. The effect of independent variables (Eudragit L-100 to Eudragit S-100 ratio and stirring speed) on the dependent variable, i.e., percentage cumulative drug release (%CDR) at 3 h and 24 h was evaluated. The optimized batch was evaluated by FT-IR, DSC study, XRD study, and SEM analysis.

RESULTS

Discrete spherical shape chitosan microspheres with entrapment efficiency of up to 95.4% were obtained and selected for coating. Chitosan microspheres coated successfully with different ratios of Eudragit L-100 to Eudragit S-100. The release profile of the optimized batch match with the desired release profile. FLBP was found to be stable and molecularly dispersed in the polymer matrix.

CONCLUSION

Taken together, it can be concluded that prepared microspheres may be considered suitable for delivering FLBP to the Ileo-colonic region of the GIT in the treatment of ulcerative colitis.

Formulation, Development and Evaluation of Budesonide Oral Nano-sponges Using DOE Approach: In Vivo Evidences

Purpose: The prevalent types of idiopathic inflammatory bowel disease are ulcerative colitis (UC) and Crohn’s disease, which affects a large number of populations. Budesonide (BUD) is a glucocorticoid with potent anti-inflammatory activity but low systemic efficacy because of high receptor affinity and rapid diversion. To overcome low efficacy and availability, a novel BUD nano-sponges was formulated using quasi- solvent diffusion and Eudragit S-100 as polymer. It was then investigated for the effect of process variables using Box-Behnken design.

Methods: The BUD Nano sponges were evaluated for particle size, particle size, polydispersity, percent drug entrapment, drug release pattern. The formulation was evaluated by an in vivo study using male Wistar rats and parameters such as clinical activity score, colon/body weight ratio (C/B ratio), macroscopic ulceration (damage score) activity were performed. Finally, histopathological examination was performed on colon tissue samples.

Results: The formulation showed better efficacy and availability as compared with the available formulations of BUD, which indicates the good efficacy of the formulated nanosponges. The clinical activity score was attenuated by the formulated nanosponges in the Wistar rats. The colon to body weight ratio was significantly reduced as compared with the control formulation. The histopathology of colon treated with nanosponges showed normal structure and architecture of the colon.

Conclusion: The results of the present work confirmed the utility of BUD nano-sponges as novel carriers in management IBD.

Synthesis, Characterization and Safety Profiling of Eudragit-Based pHResponsive Hydrogels: A Promising Platform for Colonic Delivery of Losartan Potassium

OBJECTIVE

The aim of the present study was to design an efficient delivery system with an anticipated swelling and drug release properties for a prolonged drug release as well as to target colon for various hydrophilic drugs.

METHOD

For this purpose, the pH-responsive hydrogel comprising a combination of Eudragit and acrylic acid was formed. The hydrogels were characterized for spectral (FTIR), thermal (TGA/DSC), structural (XRD), and morphological (SEM) investigations. Oral tolerability was assessed in rabbits for biocompatibility and oral use of the prepared hydrogels.

RESULTS

The results showed that an increased incorporation of Eudragit and cross-linking agent retorted the swelling, drug loading, and drug release properties at both acid (pH 1.2) and basic pH (pH 6.8 and 7.4) , while acrylic acid presented the inverse results. The oral tolerability and toxicity studies depicted that the developed hydrogels were safe up to 3800 mg/kg body weight and caused no hematological or histopathological changes when compared with the control group.

CONCLUSION

Therefore, the newly developed formulations presented adequate swelling, drug loading, release behavior, and biocompatibility properties and thus can be used as a promising tool for the colonic delivery of various hydrophilic drugs.

Colon targeted beads loaded with pterostilbene: Formulation, optimization, characterization and in vivo evaluation

Background

Pterostilbene has a proven chemopreventive effect for colon carcinogenesis but suffers low bioavailability limitations and therefore unable to reach the colonic tissue.

Objective and methodology

To overcome the issue of low bioavailability, pterostilbene was formulated into an oral colon targeted beads by ionic gelation method using pectin and zinc acetate. Optimization was carried out by 2³ factorial design whereby the effect of pectin concentration (X₁), zinc acetate concentration (X₂) and pterostilbene:pectin ratio (X₃) were studied on entrapment efficiency (Y₁) and in vitro drug release till 24 h (Y₂). The optimized beads were characterized for shape and size, swelling and surface morphology. The optimized beads were uniformly coated with Eudragit S-100 using fluidized bed coater. Optimized coated beads were characterized for in vitro drug release till 24 h and surface morphology. Pharmacokinetic and organ distribution study were performed in rats to ascertain the release of pterostilbene in colon.

Results

The optimized formulation comprised of 2% w/v of pectin concentration (X₁), 2% w/v of zinc acetate concentration (X₂) and 1:4 of pterostilbene:pectin ratio (X₃), which showed a satisfactory entrapment efficiency (64.80%) and in vitro release (37.88%) till 24 h. The zinc pectinate beads exhibited sphericity, uniform size distribution, adequate swelling and rough surface. The optimized coated beads achieved 15% weight gain, displayed smooth surface and optimum drug release. Pterostilbene from optimized coated beads appeared in the plasma at 14 h and reached the C_max at 22 h (T_max), whereas plain pterostilbene exhibited T_max of 3 h.

Discussion and conclusion

Thus, larger distribution of pterostilbene was obtained in the colonic tissue compared to stomach and small intestinal tissues. Thus, delayed T_max and larger distribution of pterostilbene in colonic tissue confirmed the targeting of beads to colon.

De-Esterified Tragacanth Microspheres Loaded into Eudragit S-100 Coated Capsules for Colon-Targeted Delivery

The objective of this study was to develop a novel bacterially-triggered micro-particular system of de-esterified tragacanth (DET) in combination with Eudragit S-100 coated capsules for colon drug delivery of 5-fluorouracil (5-FU) using microemulsion method. The loading study was conducted at different drug-to-polymer ratios and cross-linker concentrations. The maximum loading efficiency was achieved, 44.1% at 1:5 drug-to-polymer ratio and 0.7% cross-linker concentration. The FTIR results also confirmed the encapsulation of 5-FU in microspheres. The release profile was dependent on the cross-linker concentration, environmental pH, and presence of pectinase enzyme. Microspheres inserted into Eudragit S-100 coated capsules released less than 5% of the drug at stomach and small intestine pH levels, whereas 70% of the drug was released at colon pH levels, and about 25% of the drug did not release unless in the presence of pectinase enzyme. To omit burst release, microspheres were washed with water, and the release became pH independent, and was just achieved in the presence of pectinase enzyme. 5-FU loaded microspheres with an IC₅₀ value of 80 µg/mL were as effective as the free drug on HT-29. Generally, the results demonstrated that drug-loaded microspheres inserted into Eudragit S-100 coated capsules can be effective for colon-targeted delivery.

Formulation, physicochemical characterization and in vitro evaluation of human insulin-loaded microspheres as potential oral carrier

Abstract

The objective of the present investigation was to formulate and characterize the human insulin entrapped Eudragit S100 microspheres containing protease inhibitors and to develop an optimized formulation with desirable features. A w/o/w multiple emulsion solvent evaporation technique was employed to produce microspheres of human insulin using Eudragit S-100 as coating material and polyvinyl alcohol as a stabilizer. The resultant microspheres were evaluated for drug-excipient compatibility, encapsulation efficiency, particle size, surface morphology, micromeritic properties, enteric nature, and in vitro drug release studies. Micromeritic properties indicated good flow properties and compressibility. In present investigation formulation F6 with drug/polymer ratio (1:100) was found to be optimal in terms of evaluated parameters where it showed a significantly higher percentage of encapsulation efficiency (76.84%) with minimal drug release (3.25%) in an acidic environment. The optimized formulation (F6) also possessed good spherical shape and particle size (57.42 µm) required to achieve the desired in vitro drug release profile at pH 7.4. The results confirmed that human insulin-loaded Eudragit S-100 microspheres containing protease inhibitor possessed good encapsulation efficiency, pH dependant controlled release carrying encapsulated insulin to its optimum site of absorption. This ultimately resulted in enhanced insulin absorption and biological response.

Graphical Abstract

pH triggered delivery of curcumin from Eudragit-coated chitosan microspheres for inflammatory bowel disease: characterization and pharmacodynamic evaluation

OBJECTIVE

This investigation deals with the development and evaluation (in vitro and in vivo) of pH triggered Eudragit-coated chitosan microspheres of curcumin (CUR) for treating ulcerative colitis.

METHODS

CUR-loaded chitosan microspheres were initially prepared by emulsion cross linking method followed by coating with Eudragit S-100. The pharmacodynamics of the developed formulation was analyzed in mice by acetic acid induced colitis model.

RESULTS

The developed microspheres were of uniform spherical shape with high entrapment efficiency. CUR-chitosan microspheres showed less intense peaks compared to free CUR confirming inclusion of drug within microspheres as revealed by X-ray diffractogram. Uncoated CUR-chitosan microspheres exhibited burst release within initial 4 h while microspheres coated with Eudragit S-100 prevented premature release of CUR and showed controlled release up to 12 h following Higuchi model. In vivo organ biodistribution study showed negligible amount of CUR in stomach and small intestine confirming integrity of microsphere in upper gastrointestinal tract (GIT). In vivo study revealed significant reduction in severity and extent of colonic damage with CUR-loaded microspheres as compared to pure CUR which was further confirmed by histopathological study.

CONCLUSION

In vitro and in vivo studies proved the developed formulations as a promising system for pH-dependent delivery of drug to colon in ulcerative colitis.

Factorial design-based development of measlamine microspheres for colonic delivery

For treating colonic diseases, conventional oral drug delivery systems are not effective, as they fail to reach the appropriate site of action. Thus, there is a need to develop effective and safe therapy for the treatment of colonic disorders. The aim of the present study was to design a colon-specific delivery system for an anti-inflammatory drug, mesalamine, with minimal degradation and optimum delivery of the drug with relatively higher local concentration, which may provide more effective therapy for inflammatory bowel disease including Crohn disease and ulcerative colitis. Factorial designs (four factors and two levels) for eudragit S-100 (pH-dependent polymer)-coated, pectin (natural polysaccharides)-based microspheres of mesalamine were constructed and conducted in a fully randomized manner to study all possible combinations. Based on the desirability function formulation, F14 was found to be the best formulation. The overall desirability coefficient of formulation F14 was found to be 0.825. The formulation F14 was subjected to in vitro release studies, and the results were evaluated kinetically and statistically. The microspheres started releasing the drug at the beginning of 7th hour, which corresponds to the arrival time at proximal colon. The cumulative percent drug release for formulation F14 at the end of 16 h was found to be 98%. The release kinetics showed that the release followed the Higuchi model, and the main mechanism of drug release was diffusion. The study presents a new approach for colon-specific drug delivery.

Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system

The purpose of the present investigation was to prepare matrix tablets of naproxen using a hydrophobic polymer, i.e., Eudragit RLPO, RSPO, and combination of both, by wet granulation method. The tablets were further coated with different concentrations of Eudragit S-100, a pH-sensitive polymer, by dip immerse method. In vitro drug release studies of tablets were carried out in different dissolution media, i.e., 0.1 N HCl (pH 1.2), phosphate buffers pH 6.8 and 7.4, with or without rat cecal content. The swelling studies of the optimized formulation were carried out. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The effect of dissolution medium on the surface of matrix tablet was determined by using Scanning Electron Microscopy technique. The stability studies of all formulations were performed as per ICH guidelines. The results demonstrated that the tablets coated with Eudragit S-100 (2% w/v) showed a sustained release of 94.67% for 24 h, but drug release increased to about 98.60% for 24 h in the presence of rat cecal content while the uncoated tablets released the drug within 5 h. With regard to release kinetics, the data were best fitted with the Higuchi model with non-Fickian drug release kinetics mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions for 6 months. The enteric-coated Eudragit S-100 coated matrix tablets of naproxen showed promising site-specific drug delivery in the colon region.